Hancock's Applied Mechanics for Engineers - N C Riggs

PREFACE In the preperation of this book the author has had in mind the fact that the student finds much difficulty in seeing the applications of theory to practical problems. For this reason each new principle developed is followed by a number of applications. In many cases these are illustrated, and they all deal with matters that directly concern the engineer. It is believed that problems in mechanics should be practical engineering work. The author has endeavored to follow out this idea in writing the present volume. Accordingly, the title Applied Mechanics for Engineers has been given to the book. The book is intended as a text-book for engineering students of the Junior year. The subject-matter is such as is usually covered by the work of one semester. In some chapters more material is presented than can be used in this time. With this idea in mind, the articles in these chapters have been arranged so that those eomirlg last may be omitted without affecting the continuity of the work. The book contains more problems than can usually be given in any one semester. While it is difficult to present new material in the matter of principles, much that is new has been introduced in the applications of these principles. The subject of Couples is treated by representing the couples by means of vectors. The author claims that the chapters on Rlonlent of Inertia, Center of Gravity, Work and Energy, Friction and Impact are more complete in theory and applications than those of ally othez - American text-book on the same subject. These are matters upon which the engineer frequently needs information frequent reference is, therefore, given to original sources of information. It is hoped that these chapters will be especially helpful to engineers as well as to students in college, and that they will receive much benefit as a result of looking lip the references cited. In general, the answers to the problems have been omitted for the reason that students who are prepared to use this book, should be taught to check their resuIts and work independently of any printed answer. The author wishes to acknowledge the helpful suggestions obtained from the many standard works on mechanics. An attempt has been made to give the specific reference to the original for material taken from engineering works or periodical literature. He wishes, more- over, to express his thanks to Dean C. H. enjarnin and Professor L. V. Ludy for their careful reading of the manuscript, to Professor W. I. Hatt for many of the problems used, and to Dean JV. F. M, Goss, whose con- tinued interest and advice have been n constant source of inspiration. It is hoped that the work may be an inspira- tion to students of engineering. IN the revision of this text, although rather extensive changes in method of treatment have been made in certain parts, the general subject matter and order of arrangement have been, in the main, retained. The chapter on Dynamics of Rlachinery, now called Dynamics of a Rigid Body, has been transferred to a later position in the book on account of its relatively greater difficulty. An important change is to be found in the much larger use of graphical methods. The graphical and analytical methods have been developed simultaneously ailcl many problems are given to be solved by both methods. The use of graphical methods has brought about the introduction of considerable new material, particularly in the construction of stress diagrams for trusses, and in the application of the equilibriunl polygon to centers of gravity of plane areas, to weighted strings and linkages, and to bending moment diagrams...